Biological treatment of wastewater or sewage is known and has been used for some time to remove solids and clarify the wastewater for reuse or for safer disposal. A number of different system configurations are possible. In one configuration, the wastewater is in a tank, and at the top or bottom of the tank is a mechanism for dispersing a fluid into the wastewater. The term “fluid” as used herein, is intended to include a substance, such as a liquid or gas, that is capable of flowing and that changes its shape at a steady rate when acted upon by a force tending to change its shape. The dispersed fluid used in wastewater treatment is most commonly air.
The fluid dispersion mechanism at or near the bottom of the tank typically effects an upward movement of the wastewater in the tank. This movement or rolling of the wastewater is important to keeping the suspended solids in suspension and is essential to effect the needed mixing of the tank contents for the biological process which is carried out in the tank. The use of a dispersed fluid, such as air, is intended to supply the microorganisms of the biological process with the required dissolved oxygen. For that purpose, the air is diffused or discharged as bubbles of a predetermined size to provide the maximum possible air-water interface area per volume of air. The partial pressures of the free and dissolved oxygen then determine the rate of transfer of oxygen from the air to the water. The length of time the bubbles remain in the liquid is in part a function of the efficiency of the tank.
Known systems include a number of different configurations for dispersing a fluid into wastewater. Some configurations include a mechanism positioned within the wastewater (e.g., submerged), and other configurations include a mechanism positioned on top of the wastewater (e.g., rotating contactor). These systems are generally complicated assemblies that require extensive time and effort to manufacture, transport, and install.
There remains the need to provide systems and methods for dispersing a fluid that are modular in configuration to reduce the time and costs of manufacture, transportation, and installation.